Anti-psoriatic and immunomodulatory evaluation of psorospermum febrifugum spach and its phytochemicals

Psorospermum febrifugum Spach is a flowering plant belonging to the family Hypericaceae. It has a long history for its use in folk-loric medicines as a remedy for leprosy, epilepsy, insomnia, anxiety, subcutaneous wounds and skin diseases. The study was done to evaluate the antipsoriatic and immunomodulatory properties of the leaf and stem bark extracts and fractions of P. febrifugum. The study also aimed to identify the phytochemical content of the most active fraction using TLC-GC-MS analysis. Aqueous and ethanolic extracts from the leaf and stem bark were prepared and tested for activities using the 2, 4-dinitrofluorobenzene (DNFB) induced psoriasis model. Subsequently, the more active ethanol extract of the stem bark was fractionated and tested for activities using antiinflammatory, haematological and HA models. The TLC separation gave three bands which were subjected to GC-MS analysis for phytochemical identification. Across the studied parameters (EDT, EW, and ET), the ethanolic stem bark extract showed better antipsoriatic activity (93.15%) irrespective of solvent system. Separation of this active extract yielded HF, DCM, EtOAc and MF fractions whose 200 and 400 mg/kg body weight dose respectively reduced epidermal thickness of the studied rats by 18.25-71.12% and 35.77-93.11%. Forty-two phytochemicals were identified from the GC-MS chromatogram of the most active DCM fraction and they are mostly fatty acids. The study showed that P. febrifugum exhibited excellent antipsoriatic and immunomodulatory activities. Haematological and HA titre revealed immunosuppression and strongly indicate that extracts of P. febrifugum Spach is a potential source of effective drug against psoriasis. (C) 2019 The Author(s). Published by Elsevier B.V. on behalf of African Institute of Mathematical Sciences / Next Einstein Initiative.